MCP Command Runner Doctor
Build the smallest safe wrapper for MCP configs that fail with spawn npx ENOENT, uvx ENOENT, or GUI PATH drift before you rewrite server code. This page runs locally in the browser and does not ask for config contents.
Why this exists
- 1Runner missingGUI-launched clients may not inherit the terminal PATH that finds npx, uvx, node, or python.
- 2Windows wrapperSome Windows npm runners need
cmd /cso the batch shim executes correctly. - 3Safer fixTest the command wrapper with placeholder package names before sharing redacted config for deeper review.
Build a runner checklist
Use package placeholders here. Do not paste live credential values, private endpoints, customer records, private screenshots, payment data, full names, private handles, or full transaction identifiers into public issues or buyer intake.
Wrapper checklist
Source-backed problem
Windows npx wrapper issue
Public issue documenting
spawn npx ENOENT and the cmd /c wrapper pattern.
uvx ENOENT setup note
Public MCP server docs noting that uvx ENOENT can require PATH or full-path fixes.
Node child_process docs
Official docs for command spawning behavior and shell execution boundaries.
After the runner starts
- Paste only a redacted copy into the MCP Config Risk Reviewer to flag shell wrappers, package runners, broad paths, remote URLs, and sensitive env-key names.
- If no tools appear after startup, check the Claude config path doctor before assuming the command wrapper is wrong.
- Once connected, use the tools/list importer to review tool permissions before first use.